假設我們有一個實體Person，一個控制器PersonController和一個edit.jsp頁面（創建一個新的或編輯一個現有的人）控制者@RequestMapping(value = "/edit", method = RequestMethod.POST)public String editPerson(@RequestParam("fname") String fname, Model model) {    if(fname == null || fname.length() == 0){        model.addAttribute("personToEditOrCreate", new Person());    }    else{        Person p = personService.getPersonByFirstName(fname);        model.addAttribute("personToEditOrCreate", p);    }    return "persons/edit";}@RequestMapping(value = "/save", method = RequestMethod.POST)public String savePerson(Person person, BindingResult result) {    personService.savePerson(person);    return "redirect:/home";}edit.jsp<form:form method="post" modelAttribute="personToEditOrCreate" action="save">    <form:hidden path="id"/>     <table>        <tr>            <td><form:label path="firstName">First Name</form:label></td>            <td><form:input path="firstName" /></td>        </tr>        <tr>            <td><form:label path="lastName">Last Name</form:label></td>            <td><form:input path="lastName" /></td>        </tr>        <tr>            <td><form:label path="money">Money</form:label></td>            <td><form:input path="money" /></td>        </tr>        <tr>            <td colspan="2">                <input type="submit" value="Add/Edit Person"/>            </td>        </tr>    </table> </form:form>我正在嘗試上面的代碼（沒有在savePerson方法中使用@ModelAttribute批注，并且它可以正常工作。為什么以及何時需要將批注添加到person對象：@RequestMapping(value = "/save", method = RequestMethod.POST)public String savePerson(@ModelAttribute("personToEditOrCreate") Person person, BindingResult result) {    personService.savePerson(person);    return "redirect:/home";}